Concrete, so commonly accepted in buildings, bridges and in numerous other structures, is taken for granted as massive and weighty

construction material. Research towards producing a new concrete material stems out from two factors presented by two different industries that is the growing need of construction trade and by-product of cockle shell trade. The continuously growing construction industry has posed the possibility on depletion of natural aggregates in the future that would increase the cost of concrete material. This fact has been addressed Alshahwany who highlighted that the natural resource decrease while the demand for aggregate to be used in concrete production is still high. Anticipating this issue, various types of waste materials have been investigated their potential to be used as partial coarse aggregate replacement material in concrete production such as oil palm shell, periwinkle shell, recycled coarse aggregate and others. However, to the best of authors knowledge no work has been reported on the use of cockle shells as partial coarse aggregate replacement in concrete. Owing to liberalization, privatization, and globalization, the construction of important infrastructure projects like Expressways, Airports, nuclear plants etc in India is increasing year after year. Such developmental activities consume large quantity of precious natural resources. This leads to faster depletion of natural resources on one side and manifold increase in the cost of construction of structures on the other side pose severe problem for the construction sector. This problem is very severe in developing countries like India. In view of this, people have started searching for suitable other viable alternative materials which could be used either as an additive or as a partial replacement to the conventional ingredients of concrete so that the existing natural resources could be saved to the possible extent, and could be made available for the future generation. In this process, different industrial waste materials such as fly ash, blast furnace slag, quarry dust, tile waste, brick bats, broken glass waste, waste aggregate from demolition of structures, ceramic insulator waste, etc. have been tried as a viable substitute material to the conventional materials in concrete and has also been succeeded.

A broad spectrum of lightweight concretes is being manufactured nowadays. Initially, Romans established durability of lightweight concrete by using natural aggregates from volcanic deposits. After the development of Portland cement in the early 1800s, though, it took the discovery and development of manufactured lightweight aggregates in the early 1900s to bring structural lightweight concrete to full maturity. The primary aim of lightweight concrete is to reduce the dead weight of concrete to be used in a structure which then allows a designer to reduce the size of structural elements (columns/beams) and size of foundation as well. Lightweight material has high potential to reduce the seismic mass of the structure and thereby reduce the level of seismic forces acting on a structure. Many experimental works have been carried out to improve the properties of the concrete by adding new materials; the materials may be natural materials or recycle materials or synthetic materials. The additional (new) material can be replacing the aggregate or cement or just as additive, however, many of these additional materials are used as aggregate for the production of lightweight concrete. The main natural lightweight aggregates (LWAs) are diatomite, pumice, scoria, volcanic cinders and tuff (Neville and Brooks, 2008) and the most popular way of achieving light weight concrete (LWC) production is by using LWA (Polat et al., 2010). A lot of research has been conducted on the structural performance of lightweight aggregate concrete; these are mostly confined to naturally occurring aggregates, manufactured aggregates, and aggregates from industrial by-products. Numerous achievements have been made in this regard and the subject is attracting attention due to its functional benefit of waste reusability and sustainable development. Reduction in construction costs and the ability to produce light-weight structures are added advantages. This has lead towards the effort of integrating this waste cockle shell as one of the mixing ingredient in concrete production thus opening a new horizon in agro concrete research and at the same time offering alternatives to preserve natural coarse aggregate for the use of future generation. Success in incorporating this material as partial coarse aggregate replacement in concrete making would contribute towards

reduction in the quantities of cockle shell ending up as waste. The present paper investigates the performance of concrete mix in terms of workability and compressive strength upon addition of this waste cockle shell as partial coarse aggregate replacement material.